diff --git a/include/math.h b/include/math.h
new file mode 100644
index 0000000..661e588
--- /dev/null
+++ b/include/math.h
@@ -0,0 +1,3 @@
+#define sgn(x) ((x<0)?-1:((x>0)?1:0));
+                                        
+u32 abs(int x);